Method and apparatus for creating scramble signals in RFID

• US 20070016944A1
• Filed: 06/23/2006
• Published: 01/18/2007
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Seknion Incorporated
• Original Assignee: Seknion Incorporated
• Inventors: Hansen, Thorkild
• Granted Patent: US 7,889,054 B2
• Time in Patent Office: Days
• US Class Current: 726/9
• CPC Class Codes: G06K 19/07336 Active means, e.g. jamming or scrambling of the electromagnetic field
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10267 the arrangement comprising a circuit inside of the interrogation device
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04K 2203/20 for contactless carriers, e.g. RFID carriers record carriers with integrated circuit chips including means for preventing undesired reading or writing from or to record carriers by hindering electromagnetic reading or writing G06K19/07318; arrangements for sensing record carriers including arrangements for protecting the interrogation against piracy attacks G06K7/10257
• CPC Class Codes: H04K 2203/32 including a particular configuration of antennas
• CPC Class Codes: H04K 2203/34 involving multiple cooperating jammers
• CPC Class Codes: H04K 3/43 characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
• CPC Class Codes: H04K 3/44 characterized by the control of the jamming waveform or modulation type
• CPC Class Codes: H04K 3/825 by jamming
• CPC Class Codes: H04K 3/86 related to preventing deceptive jamming or unauthorized interrogation or access, e.g. WLAN access or RFID reading record carriers with integrated circuit chips including means for preventing undesired reading or writing from or to record carriers by hindering electromagnetic reading or writing G06K19/07318; arrangements for sensing record carriers including arrangements for protecting the interrogation against piracy attacks G06K7/10257

Abstract

The disclosed inventions relate to a method and apparatus for creating scramble signals. The disclosed inventions further relate to a method and apparatus for creating scramble signals from data signals. The disclosed inventions also relate to a method and apparatus for creating minimum-energy scramble signals. The disclosed inventions further relate to a method and apparatus for exploiting sleep and wake commands to achieve efficient data and scramble signals.

Claims

1. A method for interrogating an RFID tag using an antenna array, comprising the steps of:

generating from an RF signal source a data signal that causes said RFID tag to respond;

generating from said RF signal source one or more scramble signals that do not cause said RFID tag to respond;

passing said data signal and said one or more scramble signals through a feed network to said antenna array; and

,

receiving a response from said RFID tag when said RFID tag is located within a region where said data signal overshadows said one or more scramble signals.

2. The method of claim 1, wherein at least one of said one or more scramble signals is obtained by applying a scrambler to said data signal.

3. The method of claim 2, wherein said applying a scrambler step further comprises the step of applying a mixer.

4. The method of claim 1, wherein said data signal comprises a carrier having high values and low values and wherein said one or more scramble signals are obtained by inverting said high values and said low values of said carrier.

5. The method of claim 1, wherein said data signal and said one or more scramble signals employ sleep and wake commands.

6. The method of claim 1, wherein said one or more scramble signals employ a sleep command.

7. The method of claim 1, wherein said one or more scramble signals are minimum-energy signals.

8. A method for interrogating an RFID tag using an antenna array, comprising the steps of:

generating from an RF signal source a data signal that causes said RFID tag to respond;

generating from one or more RF scramble signal sources one or more modulated scramble signals that do not cause said RFID tag to respond;

passing said data signal and said one or more modulated scramble signals through a feed network to said antenna array; and

,

receiving a response from said RFID tag when said RFID tag is located within a region where said data signal overshadows said one or more modulated scramble signals.

9. The method of claim 8, wherein said one or more modulated scramble signals consist of intelligible bits.

10. The method of claim 8, wherein said one or more modulated scramble signals consist of unintelligible bits.

11. The method of claim 8, wherein said one or more modulated scramble signals consist of both intelligible and unintelligible bits.

12. The method of claim 8, wherein said one or more scramble signals are minimum-energy signals.

13. The method of claim 8, wherein said data signal and said one or more scramble signals employ sleep and wake commands.

14. The method of claim 8, wherein said one or more scramble signals employ a sleep command.

15. An RFID data signal and RFID scramble signal generator, comprising:

a first RF source that produces a first RF signal;

a second RF source that produces a second RF signal;

a data signal modulator that receives said first RF signal and produces said RFID data signal; and

,

a scramble signal modulator that receives said second RF signal and produces said RFID scramble signal.

16. The signal generator of claim 15 wherein said first RF source is different from said second RF source.

17. The signal generator of claim 15 further comprising an RF receiver that receives RFID tag signals.

18. An RFID data signal and RFID scramble signal generator, comprising:

an RF source that produces an RF signal;

a data signal modulator that receives said RF signal and produces said RFID data signal; and

,

a scrambler that receives said RFID data signal and produces said RFID scramble signal.

19. The signal generator of claim 18 further comprising an RF receiver that receives RFID tag signals.

20. The signal generator of claim 18 wherein said scrambler comprises a mixer that mixes said RFID data signal and a modulating signal to produce said RFID scramble signal.